Method and apparatus for making plastic tubes

ABSTRACT

A method and apparatus for manufacturing tubes bent from a foil of plastic material which is flanged on one or both ends and which may be closed by a lid on one or both ends.

United States Patent 51 3,654,037 Lieblang [4 Apr. 4, 197 2 [54] METHOD AND APPARATUS FOR R r n i ed MAKING PLASTIC TUBES UNITED STATES PATENTS 72 Inventor; Fritz Lieblang, s h f t 3 D4 w 2,058,182 10/1936 Schmidtke...v ..93/8l X Berlin 7 Germany 2,616,463 11/1952 Potchen ..93/8l X 3,396,567 8/1968 Bachmann ..72/318 1 Filed: July 24, 1969 3,466,845 9/1969 Beekes et al ..93/81 x [21] Appl' 853584 Primary Examiner-$amuelFeinberg Assistant Examiner-J. M. Haniey [S2] U.S.Cl 156/512, l56/218,93/81 [51] lnt.Cl. ...B32b31/02,B32b31/16 [57] ABSTRACT [58] Field ofSeai-ch ..156/218, 383-385,

A method and apparatus for manufacturing tubes bent from a foil of plastic material which is flanged on one or both ends and which may be closed by a lid on one or both ends.

11 Claims, 14 Drawing Figures Patented April 4, 1972 4 Sheets-Sheet 1 Inventor.-

Patented April 4, 1972 4 Sheets-Sheet 2 Patented April 4, 1972 3,654,037

4 Sheets-Sheet I5 Fig. 12

Patented April 4, 1972 4 Sheets-Sheet 4 Fig. I

Inventor:

Fig. 14

METHOD AND APPARATUS FOR MAKING PLASTIC TUBES The present invention relates to a method for manufacturing tubes, in particular tubes, which are bent from a foil of plastic material, which is to be flanged on one or both ends and which may be closed by a lid on one or both ends, the ready tube is mainly used for packing purposes. The invention is also concerned with suitable apparatus which may be em ployed in carrying out such method.

According to a known method of manufacture, such tubes have been made hitherto by cutting a piece of foil from a roll of plastic foil, the width of said piece of foil being equivalent to the circumference of the tube to be formed, the piece of foil being conveyed to a forming cylinder over which said piece of foil was folded and the overlapping edges of the foil were glued together by applying a solvent or an adhesive. The tube of foil, produced by this method was cut to the desired length of the tube by a cutting device. These tubes were conveyed to a flanging machine, arranged separately from the aforementioned forming cylinder and the tube was inserted by hand into said machine. The flanging of the edges of the tube was effected by heated flanging disks of known design, equipped with annular flanging grooves, which disks were moved under pressure against the ends of the tube, and a rotating motion was carried out simultaneously. The transporting of the preformed tubes from the tube folding device to the flanging machine necessitated on one hand an additional operating time and on the other hand, additional labor was required to run both machines. The arrangement of separate machinery used hitherto has the disadvantage of an uneconomical production. A further disadvantage of the known flanging machine is the fact, that the flanging disks could not be heated to a temperature higher than the yield point of the material of the plastic foil, otherwise the flowing material would follow the rotating flanging disks, thus preventing the formation of a perfect flange.

An object of the present invention is a method by which the formation of the tube from the foil and also the flanging operation is accomplished in a single working operation carried out on one end the same machine, thus reducing the operating time and labor which was required for the production of such tubes as it was hitherto and producing more economical.

A further advantage of the method according to the invention is the fact, that the flanging operation is effected by means of flanging disks which carry out an oscillating movement. By this measure, it is possible to increase the temperature above the yield point of the plastic material of the foil, whithout preventing the formation of a perfect flanging edge, since the oscillating movement of the flanging disks causes the flowing material to remain practically at the same point.

The present invention is a process for manufacturing tubes bent from a foil of plastic material, which are flanged on one or both ends and which may be closed by a lid on one or both ends characterized in that a piece of foil which is cut to the required length is introduced into a longitudinal slot of a forming cylinder, the diameter of which is equivalent to the diameter of the tube to be formed and that the foil is ejected out of said forming cylinder by axially shifting said foil whilst applying a stream of adhesive to the jointing ends of the tube which is formed from said foil and that the ejected tube is received by conveyor means which transfer said tube to a flanging apparatus by intermittently shifting or rotating said tube, in which flanging apparatus one or both'ends of said tube are provided with flanges and that the flanging operation is carried out by flanging disks, exerting an axial pressure on said end or ends of said tube and that said flanging tubes carry out an oscillating movement simultaneously.

A further object of the invention is an apparatus for carrying out the method, characterized in that a forming cylinder is provided with a longitudinal slot extending over the total length of said cylinder and' that said longitudinal slot is adapted to receive a foil and that inside of said cylinder a reciprocating piston is provided, and that on one end of said cylinder conveyor means are provided, which consist of two magnets, adapted to exert an axial movement and oscillating movements on said flanging disks.

According to a preferred embodiment of the invention, the apparatus is characterized in that the piston inside the forming cylinder comprises a bottom plate, having a diameter smaller than the inner diameter of said forming cylinder and a head piece of the same diameter which is shiftable in axial direction relative to said bottom plate against the resistance of a spring and that the bottom plate is equipped with a set of laminated springs arranged around the periphery of said bottom plate, and that the laminatedsprings spanthe annual gap existing between the piston and the inner wall of the forming cylinder and that said springs extend as far as to the head piece of the piston.

According to other features of the invention, the apparatus is characterized in that the forming cylinder is provided with a stop piece on one of its free ends, having the diameter of the piston which is equipped with an annular spiral spring, which is in contact with the inner wall of the forming cylinder, and that an adjusting device is provided at the free end of the forming cylinder, adapted to change the diameter of the delivery opening of the forming cylinder and that a nozzle is arranged at the carrier end of the longitudinal slot of the forming cylinder through which nozzle a stream of a solvent or of an adhesive is pumped by means of an intermittently driven pump and that said stream of solvent or adhesive is applied on to the foil.

According to further features of the invention, the apparatus is also characterized in that pawls are arranged on working tables which receive the carriers, which are adapted to open the collet chucks and that said pawls are preferably actuated by electromagnetic means, and that, a rotating separating knife is provided, which is arranged vertically to the axis of the tube and which is adapted to be moved into the path of conveyance of the carriers for the urpose of cutting through a flanged tube received in said carriers, and that an electrical control device of known design is provided, controlling the sequence of actuation of the piston, the pump, the carriers, the pawls and the flanging disks and that a working table is provided, leading to the longitudinal slot of the forming cylinder, which is equipped with conveyor rollers and a deflection roll which facilitate the guiding of the foil into the said slot and that the working table is preceded by a cutting device and a printing apparatus for applying an imprint on the foil and that the pieces of foils are cut off from a roll of material.

The invention will now further be described and a number of preferred embodiments of the invention are illustrated in the accompanying drawing in which:

FIG. 1 is a plan view of the apparatus in diagrammatical representation,

FIG. 2 is a side view ofFIG. l, I

FIG. 3 is a plan view of the driving device of the flanging disks,

FIG. 4 is a sectional view along the lines A-B in FIG. 1,

FIG. 5 is a sectional view along the line C-D in FIG. 1, with the caller chucks in locked position,

FIG. 6 is a view according to FIG. 5, but with the collet chucks in open position,

FIG. 7 is a view of the flanging disk,

FIG. 8 is a sectional side view of FIG. 7,

FIG. 9 is an enlarged partial view of FIG. 8,

FIG. 10 is a cross-sectional view of the forming cylinder with the piston,

FIG. 11 is a longitudinal section view of the forming cylinder,

FIG. 12 is an enlarged partial view of FIG. 11,

FIG. 13 is a schematical representation of the working table,

FIG. 14 is a schematical representation of an automatic foil conveyor.

A device according to the invention comprises two-work tables l and 2, which are arranged shiftable against each other and connected by connecting pieces 3. Work table 1 supports a folding cylinder 4, with a longitudinal slot 5, into which a piece of foil 11, shown in FIG. 14 can be inserted. Inside the cylinder 4 is a piston 6, which is adapted to carry out a reciprocating movement inside said cylinder 4; said piston 6 is driven by a conventional driving device by means of gear wheels 9 which engage in a piston rod 8. The length of stroke of the piston 6 inside the casing 4 is adjustable to the desired length of stroke by means of adjustable limit switches. As shown in FIG. 11, the piston 6 comprises a bottom plate 12 and a head piece 13; said head piece 13 is shiftably mounted on a pin 14 on which it can be moved against the resistance of a compression spring 15. As shown in FIG. and 12, a set of laminated spring 16, are fastened around the circumference of the bottom plate 12 and are arranged in axial direction of the cylinder 4. The lateral edges of the laminated springs 16 are supported on the inner wall of the cylinder 4, thus bridging the annular gap between the piston 6 and the inner wall of the cylinder 4. The ends of the laminated springs 16 extend as far as to the head piece 13 of the piston 6. A piece of foil 11 is inserted through the longitudinal slot 5 into the cylinder 4, where it assumes the form ofa tube, said tube will be ejected through the ejection opening of the cylinder 4 by the movement of the piston 6, aided by the laminated springs 16. During the process of ejection, the head piece 13, which is slidably mounted on a guide rod 17, extending along the center of the cylinder 4, comes in contact with an end piece 18, which is fastened to the end of the guide rod 17. At the moment ofcontact, the head piece 13 is pressed back against the end piece 18, whereby the resistance of a spring is overcome, so that the foil, which is formed into a tube is entirely ejected from the cylinder 4 by aid of the laminated springs 16.

In the circumferential groove of the end piece 18, an annular coil spring 19 is received, which is supported on the inner wall of the cylinder 4. The annual coil spring 19 serves to fit the foil to be ejected to the exact diameter of the cylinder 4. The cylinder 4 is also equipped with an adjusting device, which is not shown in the drawings, which enables to decrease of the width of the longitudinal slot 5, thereby also decreasing the LB. of the cylinder 4. The alteration of the diameter permits the production of tubes made of foil and also of the lids for closing the ends of said tube, the diameter of the lids must be slightly larger. A nozzle 20 is arranged in the vicinity of the ends of the longitudinal slot 5 of the cylinder 4, through which a stream of adhesive is fed by means of an intermittently actuated pump 21 in such a manner, that a stream of adhesive emerges from said nozzle and is applied to the overlapping lateral edges of the foil, which stream of adhesive is equally distributed along said edges and by which stream the foil is glued together in the form ofa tube.

On the work table 1 near the cylinder 4, a motor 26 is mounted, which serves as a servo motor, driving a shaft via a gear unit. On said shaft 25, a carrier 22 is firmly secured and a carrier 23 is slidably attached to it. As shown in FIG. 1, the foil, which was formed into a tube 24 is inserted between the carriers 22 and 23. For this purpose, the carriers 22 and 23, as shown in FIG. 5 and 6, are equipped with two collet chucks 28 and 29. While the carriers 22 and 23 are in their receiving position, one of the collet chucks 28 and 29 is situated close to the end of the cylinder 4, while the other chuck of the collet chucks 28 and 29 is situated between the flanging disks 34. The component 29 of the collet chuck is provided with a cam 30, which engages on the pawl 31 when the receiving position is attained and the collet chucks 28 and 29 are opened by action of the spring 33. As soon as the tube 24, being ejected from the cylinder 4 has attained the position shown in FIG. 1, an electromagnet 32 is exited and the pawl 31 opens, so that the collet chucks 28 and 29 are locked. Hereafter, the carriers 22 and 23 are turned around by means of the servo motor 26 and the tube 24, which is glued together enters the space between the flanging disks 34. The flanging disks are connected to driving means 35, comprising a magnet 36, as shown in FIG. 2, pressing the flanging disk 34 against the edge of the tube 24 and a set of magnets 37, causing the flanging disk 34 to oscillate; said set of magnets 37 constitutes in co-operation with a set of springs 37a, shown in FIG. 3, a system capable of oscillating. This oscillating system can be adjusted in a simple manner to various amplitudes and rates of oscillation and can thus be adapted to any case of application which may occur.

The axle 25 of the carriers 22 and 23 of the conveying device rotates in a clockwise direction. Below the axle 25, a cutting knife 38 is provided, which is driven by the motor 39. The cutting knife 38 is adapted to penetrate into the passage of conveyance of the tube already flanged, cutting it in two halves, which are normally used as lids for the tubes. Instead of the cutting knife, a glow wire may be used.

The various members of the device may be controlled by an electronically operated control device 40 of known design.

As shown in FIG. 13, the longitudinal slot 5 of the cylinder 4 is associated with a table 41 placed against said slot, onto which table the pieces of foil may be laid on by hand. At the end of the table is a deflection roll 42, by aid of which the pieces of foil are guided into the slot 5 of the cylinder 4, assisted by a deflection plate 43. The foils may be guided into the slot by means of conveyor rollers, not shown in the drawings.

FIG. 14 illustrates a feeding device in connection with a foil roll, the foil strips are pulled off the roll 48 by means of the conveyor rolls 47 and are guided to a table 45 arranged horizontally, above which table a printing device may be provided. At the end of the table 45 is a cutting knife 44 which is cutting the conveyed foil to the desired length of foil, which are hereafter conveyed via conveyor rolls 47 to the feeding table 41, from which table the foil cuttings 11 are fed into the longitudinal slot 5 of the cylinder 4.

What I claim is 1. Method for manufacturing tubes, bent from a foil of plastic material, which is flanged on one or both ends and which may be closed by a lid on one or both ends, characterized in that a piece of foil which is cut to the required length is introduced into a longitudinal slot of a forming cylinder, the diameter of which is equivalent to the diameter of the tube to be formed and that the foil is ejected out of said forming cylinder by axially shifting said foil and applying simultaneously a stream of adhesive to the jointing ends of said tube which is formed from the said foil and that the ejected tube is received by conveyor means which transfer said tube to a flanging apparatus by intermittently shifting or rotating said tube, in which flanging apparatus one or both ends of said tube are provided with flanges, which operation is carried out by flanging disks known per se, which exert an axial pressure on the end or ends of said tube and that said flanging disks carry out an oscillating movement.

2. Apparatus for manufacturing tubes, bent from a foil of plastic material, which is flanged on one or both ends and which may be closed by a lid on one or both ends, characterized in that a forming cylinder is provided with a longitudinal slot, extending over the total length of said cylinder and that said longitudinal slot is adapted to receive a foil and that inside said cylinder a reciprocating piston is provided and that on one end of said cylinder conveyor means are provided, which consist of two carriers the distance of which can be adjusted, which are adapted to be rotated around an axis, which is parallel to the axis of the forming cylinder and that said carriers are disks which are equipped with collet chucks, mounted in the vicinity of the periphery of said carriers and that said collet chucks are arranged opposite to one another and that they are adapted to receive tubes, which are glued together and that each carrier is associated with flanging disks which are equipped with a set of magnets adapted to exert an and that said springs extend as far as to the head piece of the piston.

4. Apparatus according to claim 2, forming cylinder is provided with a free ends, having the diameter of the with an annular spiral spring, wall of the forming cylinder.

5. Apparatus according to claim 2, characterized in that an adjusting device is provided at the free end of the forming cylinder, adapted to change the diameter of the delivery opening ofthe forming cylinder.

6. Apparatus according to claim 2, characterized in that a nozzle is arranged at the carrier end of the longitudinal slot of the forming cylinder through which nozzle a stream of a solcharacterized in that the stop piece on one of its piston which is equipped which is in contact with the inner vent or of an adhesive is pumped by means of an intermittently driven pump and that said stream of solvent or adhesive is applied onto the foil.

7. Apparatus according to claim 2, characterized in that pawls are arranged on the working tables, which receive the carriers, which are adapted to open the collet chucks and that said pawls are preferably cutting through a flanged tube, received in said carriers.

9. Apparatus according to claim 2, characterized in that an electrical control device of known design is provided, controlling the sequence of actuation of the piston, the pump, the carriers, the pawls and the flanging disks.

10. Apparatus according to claim 2, characterized in that a working table is provided, leading to the longitudinal slot of the forming cylinder, which is equipped with conveyor rollers and a deflection roll, which facilitate the guiding of the foil into the said slot.

11. Apparatus according to claim 2, characterized in that the working table is preceded by a cutting device'and a printing apparatus for applying an imprint on the foil and that the pieces of foils are cut off from a roll of material. 

2. Apparatus for manufacturing tubes, bent from a foil of plastic material, which is flanged on one or both ends and which may be closed by a lid on one or both ends, characterized in that a forming cylinder is provided with a longitudinal slot, extending over the total length of said cylinder and that said longitudinal slot is adapted to receive a foil and that inside said cylinder a reciprocating piston is provided and that on one end of said cylinder conveyor means are provided, which consist of two carriers the distance of which can be adjusted, which are adapted to be rotated around an axis, which is parallel to the axis of the forming cylinder and that said carriers are disks which are equipped with collet chucks, mounted in the vicinity of the periphery of said carriers and that said collet chucks are arranged opposite to one another and that they are adapted to receive tubes, which are glued together and that each carrier is associated with flanging disks which are equipped with a set of magnets adapted to exert an axial movement and oscillating movements on said flanging disks.
 3. Apparatus according to claim 2, characterized in that the piston inside the forming cylinder comprises a bottom plate having a diameter smaller than the inner diameter of said forming cylinder and a head piece of the same diameter, a spring, said head piece being shiftable in axial direction relative to said bottom plate against the resistance of said spring and that the bottom plate is equipped with a set of laminated springs arranged around the periphery of said bottom plate, and that the laminated springs span the annual gap existing between the piston and the inner wall of the forming cylinder and that said springs extend as far as to the head piece of the piston.
 4. Apparatus according to claim 2, characterized in that the forming cylinder is provided with a stop piece on one of it''s free ends, having the diameter of the piston which is equipped with an annular spiral spring, which is in contact with the inner wall of the forming cylinder.
 5. Apparatus according to claim 2, characterized in that an adjusting device is provided at the free end of the forming cylinder, adapted to change the diameter of the delivery opening of the forming cylinder.
 6. Apparatus according to claim 2, characterized in that a nozzle is arranged at the carrier end of the longitudinal slot of the forming cylinder through which nozzle a stream of a solvent or of an adhesive is pumped by means of an intermittently driven pump and that said stream of solvent or adhesive is applied onto the foil.
 7. Apparatus according to claim 2, characterized in that pawls are arranged on the working tables, which receive the carriers, which are adapted to open the collet chucks and that said pawls are preferably actuated by electromagnetic means.
 8. Apparatus according to claim 2, characterized in that a rotating separating knife is provided, which is arranged vertically to the axis of the tube and which is adapted to be moved into the path of conveyance of the carriers for the purpose of cutting through a flanged tube, received in said carriers.
 9. Apparatus according to claim 2, chaRacterized in that an electrical control device of known design is provided, controlling the sequence of actuation of the piston, the pump, the carriers, the pawls and the flanging disks.
 10. Apparatus according to claim 2, characterized in that a working table is provided, leading to the longitudinal slot of the forming cylinder, which is equipped with conveyor rollers and a deflection roll, which facilitate the guiding of the foil into the said slot.
 11. Apparatus according to claim 2, characterized in that the working table is preceded by a cutting device and a printing apparatus for applying an imprint on the foil and that the pieces of foils are cut off from a roll of material. 